RS-232 to RS-485 Serial Communications Adapter

30020

35.00 USD
Qty
Price
1
$35.00 ea.

RS-232 to RS-485 - sometimes you need the flexibility that a RS-485 gives you over the simple RS232!


Description [Hide]

Power Requirements
  Requires at least two RS-232 output handshake lines for power.
RS-232 Side
Connector: DB-9 female
Signals: Passes through pins 3 (TD) and 2 (RD). Pins 7 (RTS) and 8 (CTS) are tied together. Pins 4 (DTR), 6 (DSR), and 1 (CD) are tied together.
RS-485 Side
Connector: 3 pin terminal block
Signals: Half-duplex two-wire operation only. Automatic control circuit enables driver only when transmitting. Receiver is disabled when transmitting to prevent echo back to RS-232 device. Can transmit up to 4000 feet at 19,200 baud.
Dimensions
  2.75" x 1.25" x 0.6"
7cm x 3.2cm x 1.5cm
 
No handshaking is required to control the RS-485 driver. The handshake lines are required but only to provide power to the converter. The RS-485 driver is automatically enabled during each spacing state on the RS-232 side. During the marking or idle state, the RS-485 driver is disabled and the data lines are held in the marking state by pull-up and pull-down resistors.

The SCA-321 has an internal connection to prevent data transmitted from the RS-232 port from being echoed back to the RS-232 port. The SCA-321 is used as a two wire (half duplex) RS-485 converter with a third conductor to be used as signal ground. Using a common signal ground ensures that the common mode voltage between devices falls within the specifications of RS-485. This is especially important for networked devices with opto-isolated RS-485 interfaces.

Using the SCA-321 to communicate to most RS-485 devices does not usually require any termination. Termination is used to match impedance of a node to the impedance of the transmission line being used. When impedances are mismatched, the transmitted signal is not completely absorbed by the load and a portion is reflected back into the transmission line. This reflected signal can cause communication errors especially on long cable runs using a high data rate. If termination is required, the SCA-321 only supports AC coupled terminators. One terminator should be installed on each end of a straight cable run. A typical AC termination is a 120 Ohm resistor and a 0.1 uF capacitor in series between 485(+) and 485(-).

Documentation [Hide]

You Might Also Like [Hide]

SparkFun USB to RS-485 Converter

50572

This breakout board pairs an SP3485 RS-485 transceiver with an FT232RL USB UART IC to convert a USB stream to RS-485.

$19.95 USD


Arduino USB Board (Uno R3)

50450

The Arduino Uno is the all-new replacement for the favourite and popular Arduino Duemilanove. Now shipping R3!

$29.45 USD


EFX-Tek RS-485 Adapter

27280

The EFX-Tek RS-485 adapter is an ideal solution for putting multiple microcontrollers on a custom network.

$31.46 USD


Logic Level Converter

50550

The SparkFun logic level converter is a small device that safely steps down 5V signals to 3.3V and steps up 3.3V to 5V. This level converter also works with 2.8V and 1.8V devices.

$1.95 USD


Parallax USB to Serial RS-232 Adapter

21197

The Parallax USB to RS-232 is a great little adapter that takes your mini-USB connector and converts it to a RS-232 interface!

$14.95 USD


Regular Motor 2

RM2

Need more power out of your gear motor? This is a high-power motor that fits in the same form factor as used by the GM2/3/8/9 style gear motors.

$2.25 USD


Northern Lights - SB-Firefly + Star Controller Bundle

60142

It's a microcontroller kit. It's a 3 watt RGB LED kit. Put into a blender with an appropriate amount of solder and love, it turns into a microcontrolled Northern Lights RGB Bundle! This little guy can produce greens, violets, and teals that make you feel like you're north of the 49th parallel.

$36.75 USD


22µF Capacitor

CP22uF

22uF 16V Electrolytic capacitor, great for smoothing power spikes.

$0.25 USD


SeeedStudios Long Range RF Link Kits w/ Encoder and Decoder

30303

You want to make this thing talk to that thing waaay over there? Try the SeeedStudio super-long range 433Mhz RF link bundle! They're claiming 2KM range for wireless data transport & remote control use!

$18.95 USD


ProtoBoard-3U, 6-hole Strips, 1 sided, 100x160mm

20928

This traditional soldering protoboard is very similar to a solderless breadboard, but also accommodates a 96-pin VME backplane connector for slotting connectivity.

$10.78 USD


Currency


Login

Email:

Password:

Remember Me

Forgot Your Password?

Don't Have an Account?
Sign Up!